CN113058641B - Copper-iron molecular sieve based catalyst and preparation method and application thereof - Google Patents

Copper-iron molecular sieve based catalyst and preparation method and application thereof Download PDF

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CN113058641B
CN113058641B CN202110231045.XA CN202110231045A CN113058641B CN 113058641 B CN113058641 B CN 113058641B CN 202110231045 A CN202110231045 A CN 202110231045A CN 113058641 B CN113058641 B CN 113058641B
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copper
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iron
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CN113058641A (en
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卢丽君
付本全
张垒
刘璞
刘尚超
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Wuhan Iron and Steel Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/80—Mixtures of different zeolites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/8621—Removing nitrogen compounds
    • B01D53/8625—Nitrogen oxides
    • B01D53/8628—Processes characterised by a specific catalyst
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/90—Injecting reactants
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0201—Impregnation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
    • B01J2229/10—After treatment, characterised by the effect to be obtained
    • B01J2229/18—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
    • B01J29/42—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively containing iron group metals, noble metals or copper
    • B01J29/46—Iron group metals or copper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/70—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65
    • B01J29/72—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65 containing iron group metals, noble metals or copper
    • B01J29/76—Iron group metals or copper
    • B01J29/7676—MWW-type, e.g. MCM-22, ERB-1, ITQ-1, PSH-3 or SSZ-25
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Abstract

The invention discloses a copper-iron molecular sieve based catalyst and a preparation method and application thereof, and belongs to the technical field of denitration catalysis in environmental protection. The catalyst comprises MCM-22 and ZSM-5 which are used as carriers, and loaded metal Cu and Fe which are used as active components, wherein the Cu content is 1.5-5.0% of the total weight of the copper-iron molecular sieve based catalyst, the Fe content is 1.5-5.0% of the total weight of the copper-iron molecular sieve based catalyst, the general formula of the copper-iron molecular sieve based catalyst is xCu/yFe-MCM-22/ZSM-5, wherein x is the mass percent content of the metal Cu in the catalyst and takes the value of 2.0-4.5%, and y is the mass percent content of the metal Fe in the catalyst and takes the value of 2.0-4.5%. The catalyst solves the problems of narrow temperature window and low denitration activity of the traditional copper-based or iron-based molecular sieve catalyst, and has good low-temperature denitration activity and wide temperature window, and the denitration efficiency of the catalyst in the temperature range of 200-500 ℃ can reach more than 80% under the condition of the standard SCR reaction atmosphere.

Description

Copper-iron molecular sieve based catalyst, and preparation method and application thereof
Technical Field
The invention relates to a molecular sieve based catalyst for selective catalytic reduction of nitrogen oxides by ammonia, belongs to the technical field of denitration catalysis in environmental protection, and particularly relates to a copper-iron molecular sieve based catalyst and a preparation method and application thereof.
Background
Nitrogen oxides (commonly called NOx, mainly containing NO) are a major pollutant in the atmosphere, which is a great hazard to the ecological environment and human health, and not only cause acid rain, but also form precursors of near-formation atmospheric ozone pollution, secondary fine particle pollution and surface water eutrophication, and the environmental problems caused thereby, together with ozone layer destruction and global climate change, become the most prominent hot spot problems in the atmospheric environment. Nitrogen oxides are mainly derived from automobile exhaust (mobile source) and coal-fired boilers (stationary source) of power plants. In recent years, in order to improve the utilization rate of fuel, oxygen-rich lean-burn internal combustion engines are mostly used for internal combustion engines, and the main pollutant of the internal combustion engines is nitrogen oxide, so that the research on reducing the nitrogen oxide under the oxygen-rich condition has great significance. Atmospheric emission standards in countries around the world impose severe restrictions on them. Because of the difficulty in treating nitrogen oxides, controlling and treating nitrogen oxide pollutants has become one of the most active subjects in the current environmental protection research.
Ammonia selective catalytic reduction technology (NH) 3 SCR) is currently the most internationally used NO X The principle of the removal is NH 3 Or urea as a reducing agent, with NO X Reduction to harmless N 2 And discharged. The key to the SCR technology is the development of highly efficient and stable catalyst systems to suit the particular environment of automotive use. The commercial catalysts of the current art are represented by V 2 O 5 -WO 3 /TiO 2 Mainly comprises the following steps. The catalyst has various defects, such as poor low-temperature activity, narrow active temperature window, poor high-temperature stability and SO 2 Oxidized, lost vanadium and polluted and the like. With the stricter environmental regulations, the traditional V 2 O 5 -WO 3 /TiO 2 The catalyst is difficult to meet the emission legislation requirements. A new generation of molecular sieve based catalyst loaded with metal ions is widely applied at home and abroad, and in the aspect of being used as an SCR catalyst, a single ion loaded molecular sieve such as Cu-SSZ-13, Fe-Beta and Fe-ZSM-5 can be used. Mixed ion supported molecular sieves, such as Cu/Fe-SSZ-13, Cu/Fe-Beta, Cu/Fe-ZSM-5, and the like, may also be used.
MCM-22 is an MWW type molecular sieve with two independent channel systems, wherein one channel system comprises twelve-membered ring large supercages which are stacked on the other through superposed six-membered rings and penetrate through a ten-membered ring window which is approximately elliptical; the other channel system is a two-dimensional sinusoidal channel, the effective aperture is ten-membered ring, and a superposed six-membered ring connected with the supercage surrounds the effective aperture. The unique pore canal system endows the catalyst with larger specific surface area and pore canal diffusion performance, and is beneficial to the dispersion of active metal species. Rutkowska et al (Applied Catalysis B: Environmental 168-169(2015) 531-539) prepared Fe/MCM-22 catalyst, NH thereof, by ion exchange method 3 The SCR has lower performance and narrower active temperature range, and simultaneously, the molecular sieve catalysts have the defects of easy poisoning by HC compounds, low hydrothermal stability and the like. Therefore, the preparation of the catalyst with wide active temperature window, no toxicity and high temperature resistance is a technical problem which needs to be solved urgently in the field.
Disclosure of Invention
In order to solve the technical problems, the invention discloses a copper-iron molecular sieve based catalyst and a preparation method and application thereof. The molecular sieve based catalyst prepared by the invention is in a standard SCR reaction atmosphere with GHSV of 60000h -1 Under the condition, the denitration efficiency in the temperature range of 200-500 ℃ can reach more than 80%.
In order to achieve the technical purpose, the invention discloses a copper-iron molecular sieve based catalyst which comprises MCM-22 and ZSM-5 which are used as carriers, and loaded metal Cu and Fe which are used as active components, wherein the content of Cu is 1.5-5.0% of the total weight of the copper-iron molecular sieve based catalyst, and the content of Fe is 1.5-5.0% of the total weight of the copper-iron molecular sieve based catalyst.
Further, the general formula of the copper-iron molecular sieve based catalyst is xCu/yFe-MCM-22/ZSM-5, wherein x is the mass percentage content of metal Cu in the catalyst and takes a value of 2.0-4.5%, and y is the mass percentage content of metal Fe in the catalyst and takes a value of 2.0-4.5%.
Further, the metals Cu and Fe are introduced into the MCM-22 and ZSM-5 carriers by an equal-volume impregnation method.
Further, the specific surface area of the copper-iron molecular sieve based catalyst is 300-600 m 2 /g。
Further, the copper-iron molecular sieve based catalyst is in a standard SCR reaction atmosphere, and GHSV is 60000h -1 Under the condition, the denitration efficiency in the temperature range of 200-500 ℃ reaches more than 80%. And comprises 100% but not more than 100%.
Further, the Cu content is 2.0% of the total weight of the copper-iron molecular sieve based catalyst, and the Fe content is 2.0% of the total weight of the copper-iron molecular sieve based catalyst.
In order to better realize the aim of the invention, the invention also discloses a preparation method of the copper-iron molecular sieve based catalyst, which is characterized by comprising the following steps:
1) preparing an MCM-22 molecular sieve matrix;
2) preparing a ZSM-5 molecular sieve matrix;
3) preparing a copper-iron molecular sieve based catalyst: and (2) dispersing the MCM-22 molecular sieve matrix prepared in the step 1) and the ZSM-5 molecular sieve matrix prepared in the step 2) into water, adding a copper source and an iron source, performing ultrasonic treatment for a period of time, uniformly stirring at room temperature, drying at 100-120 ℃ for 12 hours, and roasting in a high-temperature furnace at 500-600 ℃ for 4-8 hours to obtain the copper-iron molecular sieve based catalyst.
Further, in the step 3), the copper source comprises copper nitrate or/and copper sulfate, and the iron source comprises iron nitrate or/and iron sulfate.
In addition, the invention also discloses application of the copper-iron molecular sieve based catalyst, which is characterized in that the catalyst is applied to NH 3 Selective catalytic reduction of NO x The method is particularly applied to the field of emission control of nitrogen oxides in flue gas of thermal power plants and coking plants.
Has the beneficial effects that:
1. the copper-iron molecular sieve based catalyst designed by the invention solves the problems of narrow temperature window and low denitration activity of the traditional copper-based and iron-based molecular sieve based catalysts, and is used in the standard SCR reaction atmosphere (500ppmNO, 500 ppmNH) 3 、5％O 2 、N 2 As balance gas), GHSV is 60000h -1 Under the condition, the denitration efficiency of the catalyst can reach more than 80% within the temperature range of 200-500 ℃, and the catalyst has good low-temperature denitration activity and a wide temperature window.
2. The preparation method designed by the invention adopts MCM-22 and ZSM-5 as denitration catalyst carriers and adopts equal volume to impregnate and load active components Cu and Fe, and the preparation process is simple and efficient and has low cost.
3. The catalyst designed by the invention is used in the field of emission control of nitrogen oxides in flue gas of thermal power plants and coking plants. Particularly, the current coke-oven plant flue gas emission control strategy is to carry out desulfurization and then denitration, so that the toxic effect of dust and sulfur dioxide on the denitration catalyst is reduced, and the denitration inlet temperature is controlled within a low temperature range of about 200 ℃, so that the catalyst designed by the invention can be applied to the similar fixed source flue gas denitration control of a coke-oven plant and the like, and has a better application prospect.
Drawings
FIG. 1 is a schematic view of the internal microstructure of a catalyst prepared according to an embodiment of the present invention.
Detailed Description
The invention is further described below. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
Example 1 an MCM-22 molecular sieve substrate was prepared;
distilled water, NaOH, sodium metaaluminate, silica sol (JN-40) and Hexamethyleneimine (HMI) are taken according to the mass ratio of 65 g: 1.5 g: 0.6 g: 23.7 g: 10g of the solid-liquid mixed precursor is uniformly mixed, stirred for at least 1h, aged for 2h, crystallized for 7 days at the temperature of 170 ℃ to obtain a solid-liquid mixed precursor, then filtered and washed until the filtrate is neutral, the filter residue is directly dried overnight at the temperature of 110 ℃, then roasted for 6h in the air at the temperature of 550 ℃, the obtained solid is stirred and exchanged with 1mol/L ammonium nitrate solution for 2 times at the temperature of 80 ℃ for 2h each time, filtered and washed until the filtrate is neutral, the obtained filter residue is directly dried at the temperature of 110 ℃, and then roasted for 6h in the air at the temperature of 550 ℃ to obtain the MCM-22 molecular sieve.
Example 2 preparation of a ZSM-5 molecular sieve substrate;
distilled water, NaOH, sodium metaaluminate, silica sol (JN-40) and tetrapropylammonium hydroxide (TPAOH) are taken according to the mass ratio of 45 g: 1.6 g: 0.9 g: 20.1 g: 9.5g of the mixture is uniformly mixed, stirred for at least 1h, aged for 2h, crystallized for 3 days at the temperature of 170 ℃ to obtain a precursor of solid-liquid mixture, then filtered and washed until the filtrate is neutral, the filter residue is dried at 110 ℃ overnight, then roasted for 6h in air at 550 ℃, the obtained solid is stirred and exchanged with 1mol/L ammonium nitrate solution for 2 times at 80 ℃ and 2h each time, filtered and washed until the filtrate is neutral, the obtained filter residue is dried at 110 ℃, and then roasted for 6h in air at 550 ℃ to obtain the ZSM-5 molecular sieve.
Examples 3 to 10 were prepared for copper-iron molecular sieve based catalysts;
example 3
Dispersing 5g of MCM-22 prepared in the step 1) and 5g of ZSM-5 molecular sieve prepared in the step 2) into 50mL of water, adding 0.28g of copper nitrate trihydrate and 1.44g of ferric nitrate nonahydrate, ultrasonically dispersing for 15min, then stirring for 24h at room temperature, drying at 110 ℃, putting into a muffle furnace, and roasting for 6h at 550 ℃ in air to obtain the 1Cu/2Fe-MCM-22/ZSM-5 catalyst. Wherein, the numbers before Cu and Fe in the general formula of the catalyst all represent the mass percent content of each metal in the catalyst, and the unit is wt%, and the following examples all keep the same.
Example 4
And (2) dispersing 5g of MCM-22 prepared in the step 1) and 5g of ZSM-5 molecular sieve prepared in the step 2) into 50mL of water, adding 0.56g of copper nitrate trihydrate and 1.44g of ferric nitrate nonahydrate, performing ultrasonic dispersion for 15min, stirring at room temperature for 24h, drying at 110 ℃, and roasting in a muffle furnace at 550 ℃ for 6h to obtain the 2Cu/2Fe-MCM-22/ZSM-5 catalyst.
Example 5
Dispersing 5g of MCM-22 prepared in the step 1) and 5g of ZSM-5 molecular sieve prepared in the step 2) into 50mL of water, adding 1.12g of copper nitrate trihydrate and 1.44g of ferric nitrate nonahydrate, performing ultrasonic dispersion for 15min, stirring for 24h at room temperature, drying at 110 ℃, putting into a muffle furnace, and roasting at 550 ℃ for 6h in air to obtain the 4Cu/2Fe-MCM-22/ZSM-5 catalyst.
Example 6
Dispersing 5g of MCM-22 prepared in the step 1) and 5g of ZSM-5 molecular sieve prepared in the step 2) into 50mL of water, adding 0.56g of copper nitrate trihydrate and 0.72g of ferric nitrate nonahydrate, ultrasonically dispersing for 15min, then stirring for 24h at room temperature, drying at 110 ℃, putting into a muffle furnace, and roasting at 550 ℃ for 6h in air to obtain the 2Cu/1Fe-MCM-22/ZSM-5 catalyst.
Example 7
Dispersing 5g of MCM-22 prepared in the step 1) and 5g of ZSM-5 molecular sieve prepared in the step 2) into 50mL of water, adding 0.56g of copper nitrate trihydrate and 2.89g of ferric nitrate nonahydrate, performing ultrasonic dispersion for 15min, stirring for 24h at room temperature, drying at 110 ℃, putting into a muffle furnace, and roasting at 550 ℃ for 6h in air to obtain the 2Cu/4Fe-MCM-22/ZSM-5 catalyst.
Wherein, fig. 1 is a schematic view of the microstructure of the catalyst prepared in example 7, and it can be known from fig. 1 that the catalyst sample prepared by the present invention is a mixed morphology of MCM-22 and ZSM-5, and no obvious oxide aggregate particles are seen on the microstructure, which indicates that the metal species on the catalyst are well dispersed. The catalyst prepared by the invention is uniformly dispersed, and is beneficial to exerting the catalytic performance of the catalyst.
Example 8
On the basis of example 4, the iron source was replaced by iron sulfate.
Example 9
On the basis of example 4, the copper source was replaced by copper sulfate.
Example 10
On the basis of example 4, the iron source was changed to ferric sulfate and the copper source to copper sulfate.
Comparative example 1
Fe/MCM-22 catalyst: dispersing 5g of the MCM-22 molecular sieve prepared in the step 1) into 50mL of water, adding 1.44g of ferric nitrate nonahydrate, performing ultrasonic dispersion for 15min, stirring at room temperature for 24h, drying at 110 ℃, and then placing in a muffle furnace to roast at 550 ℃ in air for 6h to obtain the Fe/MCM-22 catalyst.
Comparative example 2
Cu/MCM-22 catalyst: dispersing 5g of the MCM-22 molecular sieve prepared in the step 1) into 50mL of water, adding 0.56g of copper nitrate trihydrate, ultrasonically dispersing for 15min, then stirring for 24h at room temperature, drying at 110 ℃, and then putting into a muffle furnace to roast for 6h at 550 ℃ in air to obtain the Cu/MCM-22 catalyst.
Comparative example 3
Fe/ZSM-5 catalyst: dispersing 5g of the ZSM-5 molecular sieve prepared in the step 2) into 50mL of water, adding 1.44g of ferric nitrate nonahydrate, ultrasonically dispersing for 15min, stirring for 24h at room temperature, drying at 110 ℃, and then putting into a muffle furnace to roast for 6h at 550 ℃ in air to obtain the Fe/ZSM-5 catalyst.
Comparative example 4
Cu/ZSM-5 catalyst: dispersing 5g of the ZSM-5 molecular sieve prepared in the step 2) into 50mL of water, adding 0.56g of copper nitrate trihydrate, ultrasonically dispersing for 15min, then stirring for 24h at room temperature, drying at 110 ℃, and then putting into a muffle furnace to roast for 6h at 550 ℃ in air to obtain the Cu/ZSM-5 catalyst.
The products prepared in the above examples 3-10 and comparative examples 1-4 are respectively granulated by a powder tablet machine to obtain 20-40 mesh catalyst samples. Putting a certain amount of catalyst into a fixed bed microreactor, and simulating the flue gas to generate NO and NH 3 、O 2 And N 2 Composition, wherein NO: 500ppm, NH 3 ：500ppm、O 2 : 5% of balance gas N 2 (ii) a The reaction temperature is 100-550 ℃, and the space velocity is 60000h -1 And before and after the reaction, smoke components are detected and analyzed by a smoke analyzer. The reaction results are shown in table 1; wherein the loading of the catalyst in table 1 remains the same.
TABLE 1 catalysts obtained in the examples for NO at different temperatures x Drop-out rate list
Figure BDA0002958103230000071
Figure BDA0002958103230000081
As can be seen from the above Table 1, the catalyst prepared by the invention has better catalytic efficiency within the temperature range of 200-500 ℃, and better catalytic performance than that of the comparative catalyst, and meanwhile, the catalyst prepared by the example 4 has the best catalytic activity.
From the above embodiments, the copper-iron molecular sieve based catalyst designed by the invention solves the problems of narrow temperature window and low denitration activity of the traditional copper-based and iron-based molecular sieve based catalysts, and is used in the standard SCR reaction atmosphere (500ppmNO, 500 ppmNH) 3 、5％O 2 、N 2 As balance gas), GHSV is 60000h -1 Under the condition, the denitration efficiency of the catalyst can reach more than 80% in a temperature range of 200-500 ℃, and the catalyst has good low-temperature denitration activity and a wide temperature window. Particularly, the current coke-oven plant flue gas emission control strategy is to carry out desulfurization and then denitration, so that the toxic effect of dust and sulfur dioxide on the denitration catalyst is reduced, and the denitration inlet temperature is controlled within a low temperature range of about 200 ℃, so that the catalyst designed by the invention can be applied to the similar fixed source flue gas denitration control of a coke-oven plant and the like, and has a better application prospect.
The raw materials listed in the invention, the upper and lower limits and interval values of the raw materials of the invention, and the upper and lower limits and interval values of the process parameters (such as temperature, time and the like) can all realize the invention, and the examples are not listed.
While the foregoing is directed to the preferred embodiment of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims (6)

1. A copper-iron molecular sieve based catalyst is characterized by comprising MCM-22 and ZSM-5 which are used as carriers, and loaded metal Cu and Fe which are used as active components, wherein the Cu content is 2.0 percent of the total weight of the copper-iron molecular sieve based catalyst, and the Fe content is 2.0 percent of the total weight of the copper-iron molecular sieve based catalyst;
the general formula of the copper-iron molecular sieve based catalyst is 2Cu/2 Fe-MCM-22/ZSM-5;
the specific surface area of the copper-iron molecular sieve based catalyst is 300-600 m 2 /g。
2. The copper-iron molecular sieve based catalyst according to claim 1, wherein the metals Cu and Fe are introduced into the MCM-22 and ZSM-5 support by an equal volume impregnation method.
3. The copper-iron molecular sieve based catalyst according to claim 1 or 2, characterized in that it is in a standard SCR reaction atmosphere, GHSV =60000 h -1 Under the condition, the denitration efficiency in the temperature range of 200-500 ℃ reaches more than 80%.
4. A method for preparing the copper-iron molecular sieve based catalyst according to any one of claims 1 to 3, which comprises the following steps:
1) preparing an MCM-22 molecular sieve matrix;
2) preparing a ZSM-5 molecular sieve matrix;
3) preparing a copper-iron molecular sieve based catalyst: dispersing 5g of MCM-22 prepared in the step 1) and 5g of ZSM-5 molecular sieve prepared in the step 2) into 50mL of water, adding 0.56g of copper nitrate trihydrate and 1.44g of ferric nitrate nonahydrate, performing ultrasonic dispersion for 15min, stirring for 24h at room temperature, drying at 110 ℃, putting into a muffle furnace, and roasting at 550 ℃ for 6h in air to obtain the 2Cu/2Fe-MCM-22/ZSM-5 catalyst.
5. Use of the copper-iron molecular sieve based catalyst according to any one of claims 1 to 3, wherein the catalyst is applied to NH 3 Use in selective catalytic reduction of NOx.
6. The application of the copper-iron molecular sieve based catalyst as claimed in any one of claims 1 to 3 is characterized in that the catalyst is particularly used in the field of emission control of nitrogen oxides in flue gas of thermal power plants and coking plants.
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"制备方法对双金属Fe-Cu-ZSM-5催化剂的NH3-SCR反应性能的影响";焦云磊等;《华东理工大学学报（自然科学版）》;20181030;第699-705页 *

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